wrangler dev consistently crashes with "access violation" (0xc0000005) on Windows 11

[Sn0wo2]

What versions & operating system are you using?

⛅️ wrangler 4.23.0, node v22.15.0, npm v11.4.2, bun v1.2.18

Please provide a link to a minimal reproduction

No response

Describe the Bug

Summary of the Problem:
The workerd runtime used by wrangler dev seems to have a critical incompatibility with my Windows environment, leading to a 0xc0000005 exception.

Troubleshooting Steps I've Exhaustively Performed:

1. Verified System Dependencies: Confirmed the latest Microsoft Visual C++ Redistributables (x64 & x86) are installed.
2. Isolated the Project: The crash occurs even with a brand new, minimal project created by npx wrangler init. This rules out my specific project's code or configuration.
3. Isolated the JS Runtime: The crash happens identically when using either Node.js v22 or Bun.
4. Isolated the Wrangler Version: Rolling back to previous versions of wrangler did not fix the issue.
5. Cleared All State: I have completely removed all .wrangler directories (both global and local) and reinstalled all node_modules.
6. Checked Environmental Factors:
   • The issue persists even after disabling my system-wide proxy.
   • The issue persists after temporarily disabling all antivirus/security software.

Environment:

版本 Windows 11 家庭中文版
版本号 24H2
安装日期 ‎2025/‎6/‎26
操作系统版本 26100.4484
体验 Windows 功能体验包 1000.26100.128.0

⛅️ wrangler 4.23.0, node v22.15.0, npm v11.4.2, bun v1.2.18

1. Run npx wrangler init hello-worker.
2. cd hello-worker.
3. Run npx wrangler dev --log-level debug.

Please provide any relevant error logs

--- 2025-07-04T13:45:13.989Z debug
🪵  Writing logs to "C:\Users\xuexu\AppData\Roaming\xdg.config\.wrangler\logs\wrangler-2025-07-04_13-45-13_808.log"
---

--- 2025-07-04T13:45:13.989Z log
Proxy environment variables detected. We'll use your proxy for fetch requests.
---

--- 2025-07-04T13:45:14.038Z log
�[90m�[39m
�[90mCloudflare collects anonymous telemetry about your usage of Wrangler. Learn more at https://github.com/cloudflare/workers-sdk/tree/main/packages/wrangler/telemetry.md�[39m
---

--- 2025-07-04T13:45:14.043Z debug
Metrics dispatcher: Posting data {"deviceId":"fc6ecee9-e5f8-4cf1-9fc8-f062638f049e","event":"wrangler command started","timestamp":1751636714043,"properties":{"amplitude_session_id":1751636714037,"amplitude_event_id":0,"wranglerVersion":"4.23.0","osPlatform":"Windows","osVersion":"Windows 11 Home China","nodeVersion":22,"packageManager":"npm","isFirstUsage":false,"configFileType":"jsonc","isCI":false,"isPagesCI":false,"isWorkersCI":false,"isInteractive":true,"hasAssets":false,"argsUsed":[],"argsCombination":"","command":"wrangler dev","args":{"xJsonConfig":true,"j":true,"latest":true,"noBundle":false,"remote":false,"r":false,"testScheduled":false,"xVectorizeBindToProd":false,"xImagesLocalMode":false}}}
---

--- 2025-07-04T13:45:14.059Z debug
.env file not found at ".env". Continuing... For more details, refer to https://developers.cloudflare.com/workers/wrangler/system-environment-variables/
---

--- 2025-07-04T13:45:14.086Z log

 ⛅️ wrangler 4.23.0
�[38;2;255;136;0m───────────────────�[39m
---

--- 2025-07-04T13:45:14.311Z debug
.env file not found at ".dev.vars". Continuing... For more details, refer to https://developers.cloudflare.com/workers/wrangler/system-environment-variables/
---

--- 2025-07-04T13:45:14.405Z debug
RemoteRuntimeController teardown beginning...
---

--- 2025-07-04T13:45:14.405Z debug
RemoteRuntimeController teardown complete
---

--- 2025-07-04T13:45:14.407Z log
�[2m⎔ Starting local server...�[22m
---

--- 2025-07-04T13:45:15.404Z error
�[31m✘ �[41;31m[�[41;97mERROR�[41;31m]�[0m �[1mThere was an access violation in the runtime.�[0m

  On Windows, this may be caused by an outdated Microsoft Visual C++ Redistributable library.
  Check that you have the latest version installed.
  See �[4mhttps://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist�[0m.


---

--- 2025-07-04T13:45:15.404Z debug
*** Received structured exception #0xc0000005: access violation; stack: 7fff04f6929f 7ff71bb12cca 7ff71bb12d93 7ff71bab13ac 7ff71bab1357 7ff71af77f1f 7ff71af78390 7ff71998385f 7ff71b103a4f 7ff71b10a976 7ff71b103f53 7ff71b10a976 7ff71b1018ec 7ff719971fc7 7ff71c2b1a7f 7fff2208e8d6 7fff2313c34b
---

--- 2025-07-04T13:45:15.407Z error
�[31m✘ �[41;31m[�[41;97mERROR�[41;31m]�[0m �[1mThere was an access violation in the runtime.�[0m

  On Windows, this may be caused by an outdated Microsoft Visual C++ Redistributable library.
  Check that you have the latest version installed.
  See �[4mhttps://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist�[0m.


---

--- 2025-07-04T13:45:15.407Z debug
*** Received structured exception #0xc00000

05: access violation; stack: 7fff04f6929f 7ff71bb12cca 7ff71bb12d93 7ff71bab13ac 7ff71bab1357 7ff71af77f1f 7ff71af78390 7ff71998385f 7ff71b103a4f 7ff71b10a976 7ff71b103f53 7ff71b10a976 7ff71b1018ec 7ff719971fc7 7ff71c2b1a7f 7fff2208e8d6 7fff2313c34b
---

--- 2025-07-04T13:45:15.478Z debug
Error in ProxyController: Could not connect to InspectorProxyWorker
 MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
    at #assembleAndUpdateConfig (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20871:13)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48) {
  code: 'ERR_RUNTIME_FAILURE',
  cause: undefined
}
---

--- 2025-07-04T13:45:15.479Z debug
=> Error contextual data: {
  config: {
    name: 'hello-worker',
    config: 'D:\\webProject\\hello-worker\\wrangler.jsonc',
    compatibilityDate: '2025-07-04',
    compatibilityFlags: [],
    complianceRegion: undefined,
    entrypoint: 'D:\\webProject\\hello-worker\\src\\index.js',
    projectRoot: 'D:\\webProject\\hello-worker',
    bindings: {},
    migrations: [],
    sendMetrics: undefined,
    triggers: [],
    env: undefined,
    build: {
      alias: undefined,
      additionalModules: [],
      processEntrypoint: false,
      bundle: true,
      findAdditionalModules: undefined,
      moduleRoot: 'D:\\webProject\\hello-worker\\src',
      moduleRules: [],
      minify: undefined,
      keepNames: undefined,
      define: {},
      custom: [Object],
      format: 'modules',
      nodejsCompatMode: null,
      jsxFactory: 'React.createElement',
      jsxFragment: 'React.Fragment',
      tsconfig: undefined,
      exports: [Array]
    },
    containers: undefined,
    dev: {
      auth: [AsyncFunction: auth],
      remote: false,
      server: [Object],
      inspector: [Object],
      origin: [Object],
      liveReload: false,
      testScheduled: false,
      persist: 'D:\\webProject\\hello-worker\\.wrangler\\state',
      registry: undefined,
      bindVectorizeToProd: false,
      multiworkerPrimary: undefined,
      imagesLocalMode: false,
      experimentalRemoteBindings: false,
      enableContainers: true,
      dockerPath: 'docker',
      containerEngine: '//./pipe/docker_engine',
      containerBuildId: '13b58346'
    },
    legacy: { site: undefined, enableServiceEnvironments: false },
    unsafe: { capnp: undefined, metadata: undefined },
    assets: undefined,
    tailConsumers: []
  },
  bundle: undefined
}
---

--- 2025-07-04T13:45:15.488Z debug
Error in ProxyController: Failed to start ProxyWorker or InspectorProxyWorker
 MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
    at #assembleAndUpdateConfig (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20871:13)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48) {
  code: 'ERR_RUNTIME_FAILURE',
  cause: undefined
}
---

--- 2025-07-04T13:45:15.488Z debug
=> Error contextual data: {
  config: {
    name: 'hello-worker',
    config: 'D:\\webProject\\hello-worker\\wrangler.jsonc',
    compatibilityDate: '2025-07-04',
    compatibilityFlags: [],
    complianceRegion: undefined,
    entrypoint: 'D:\\webProject\\hello-worker\\src\\index.js',
    projectRoot: 'D:\\webProject\\hello-worker',
    bindings: {},
    migrations: [],
    sendMetrics: undefined,
    triggers: [],
    env: undefined,
    build: {
      alias: undefined,
      additionalModules: [],
      processEntrypoint: false,
      bundle: true,
      findAdditionalModules: undefined,
      moduleRoot: 'D:\\webProject\\hello-worker\\src',
      moduleRules: [],
      minify: undefined,
      keepNames: undefined,
      define: {},
      custom: [Object],
      format: 'modules',
      nodejsCompatMode: null,
      jsxFactory: 'React.createElement',
      jsxFragment: 'React.Fragment',
      tsconfig: undefined,
      exports: [Array]
    },
    containers: undefined,
    dev: {
      auth: [AsyncFunction: auth],
      remote: false,
      server: [Object],
      inspector: [Object],
      origin: [Object],
      liveReload: false,
      testScheduled: false,
      persist: 'D:\\webProject\\hello-worker\\.wrangler\\state',
      registry: undefined,
      bindVectorizeToProd: false,
      multiworkerPrimary: undefined,
      imagesLocalMode: false,
      experimentalRemoteBindings: false,
      enableContainers: true,
      dockerPath: 'docker',
      containerEngine: '//./pipe/docker_engine',
      containerBuildId: '13b58346'
    },
    legacy: { site: undefined, enableServiceEnvironments: false },
    unsafe: { capnp: undefined, metadata: undefined },
    assets: undefined,
    tailConsumers: []
  },
  bundle: undefined
}
---

--- 2025-07-04T13:45:15.488Z debug
Error in ProxyController: Failed to send message to InspectorProxyWorker: {"type":"reloadStart"}
 MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
    at #assembleAndUpdateConfig (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20871:13)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48) {
  code: 'ERR_RUNTIME_FAILURE',
  cause: undefined
}
---

--- 2025-07-04T13:45:15.488Z debug
=> Error contextual data: {
  config: {
    name: 'hello-worker',
    config: 'D:\\webProject\\hello-worker\\wrangler.jsonc',
    compatibilityDate: '2025-07-04',
    compatibilityFlags: [],
    complianceRegion: undefined,
    entrypoint: 'D:\\webProject\\hello-worker\\src\\index.js',
    projectRoot: 'D:\\webProject\\hello-worker',
    bindings: {},
    migrations: [],
    sendMetrics: undefined,
    triggers: [],
    env: undefined,
    build: {
      alias: undefined,
      additionalModules: [],
      processEntrypoint: false,
      bundle: true,
      findAdditionalModules: undefined,
      moduleRoot: 'D:\\webProject\\hello-worker\\src',
      moduleRules: [],
      minify: undefined,
      keepNames: undefined,
      define: {},
      custom: [Object],
      format: 'modules',
      nodejsCompatMode: null,
      jsxFactory: 'React.createElement',
      jsxFragment: 'React.Fragment',
      tsconfig: undefined,
      exports: [Array]
    },
    containers: undefined,
    dev: {
      auth: [AsyncFunction: auth],
      remote: false,
      server: [Object],
      inspector: [Object],
      origin: [Object],
      liveReload: false,
      testScheduled: false,
      persist: 'D:\\webProject\\hello-worker\\.wrangler\\state',
      registry: undefined,
      bindVectorizeToProd: false,
      multiworkerPrimary: undefined,
      imagesLocalMode: false,
      experimentalRemoteBindings: false,
      enableContainers: true,
      dockerPath: 'docker',
      containerEngine: '//./pipe/docker_engine',
      containerBuildId: '13b58346'
    },
    legacy: { site: undefined, enableServiceEnvironments: false },
    unsafe: { capnp: undefined, metadata: undefined },
    assets: undefined,
    tailConsumers: []
  },
  bundle: undefined
}
---

--- 2025-07-04T13:45:15.489Z log

---

--- 2025-07-04T13:45:15.491Z error
�[31m✘ �[41;31m[�[41;97mERROR�[41;31m]�[0m �[1mThe Workers runtime failed to start. There is likely additional logging output above.�[0m


---

--- 2025-07-04T13:45:15.491Z debug
MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
    at #assembleAndUpdateConfig (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20871:13)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48)
---

--- 2025-07-04T13:45:15.491Z log
�[32mIf you think this is a bug then please create an issue at https://github.com/cloudflare/workers-sdk/issues/new/choose�[0m
---

--- 2025-07-04T13:45:15.572Z debug
Error in LocalRuntimeController: Error reloading local server
 MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
    at #assembleAndUpdateConfig (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20871:13)
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48)
    at async #waitForReady (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20946:5)
    at async #onBundleComplete (D:\webProject\hello-worker\node_modules\wrangler\wrangler-dist\cli.js:174526:33)
    at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48) {
  code: 'ERR_RUNTIME_FAILURE',
  cause: undefined
}
---

--- 2025-07-04T13:45:15.572Z debug
=> Error contextual data: undefined
---

--- 2025-07-04T13:45:17.300Z debug
Sentry: Capturing exception MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
---

--- 2025-07-04T13:45:17.308Z debug
Metrics dispatcher: Posting data {"deviceId":"fc6ecee9-e5f8-4cf1-9fc8-f062638f049e","event":"wrangler command errored","timestamp":1751636717308,"properties":{"amplitude_session_id":1751636714037,"amplitude_event_id":1,"wranglerVersion":"4.23.0","osPlatform":"Windows","osVersion":"Windows 11 Home China","nodeVersion":22,"packageManager":"npm","isFirstUsage":false,"configFileType":"jsonc","isCI":false,"isPagesCI":false,"isWorkersCI":false,"isInteractive":true,"hasAssets":false,"argsUsed":[],"argsCombination":"","command":"wrangler dev","args":{"xJsonConfig":true,"j":true,"latest":true,"noBundle":false,"remote":false,"r":false,"testScheduled":false,"xVectorizeBindToProd":false,"xImagesLocalMode":false},"durationMs":3299,"durationSeconds":3.299,"durationMinutes":0.054983333333333335}}
---

[edmundhung]

Hi @Sn0wo2 👋,

Thanks for reporting this! Could you let us know which exact version of the Microsoft Visual C++ Redistributable you have installed on your machine? We have seen this crop up before, and it's usually resolved by upgrading to the very latest VC++ Redistributable (for example, see issue #6170).

You can check and download the newest supported version here:

https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170#latest-microsoft-visual-c-redistributable-version

[Sn0wo2]

Hi @Sn0wo2 👋,

Thanks for reporting this! Could you let us know which exact version of the Microsoft Visual C++ Redistributable you have installed on your machine? We have seen this crop up before, and it's usually resolved by upgrading to the very latest VC++ Redistributable (for example, see issue #6170).

You can check and download the newest supported version here:

https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170#latest-microsoft-visual-c-redistributable-version

Hello, I've tried installing the latest version of Microsoft Visual C++ Redistributable before opening issue, here is a screenshot of my Microsoft Visual C++ Redistributable version

[Mion354D]

Same problem here. Wrangler keeps crashing/getting stuck.
Using latest C++ redistributable (till Jul 09).

And I found that when I turn on TUN mode proxy, Wrangler works well.
I live in China, where workers.dev is almost completely blocked. Issue author uses Windows in Chinese, so maybe he/she also lives in China.

Is there some necessary step in the Wrangler startup process to access the Cloudflare Worker domain without going through the system proxy? Guessing when it gets stuck, it crashes Wrangler.

[Sn0wo2]

Same problem here. Wrangler keeps crashing/getting stuck. Using latest C++ redistributable (till Jul 09).

And I found that when I turn on TUN mode proxy, Wrangler works well. I live in China, where workers.dev is almost completely blocked. Issue author uses Windows in Chinese, so maybe he/she also lives in China.

Is there some necessary step in the Wrangler startup process to access the Cloudflare Worker domain without going through the system proxy? Guessing when it gets stuck, it crashes Wrangler.

ty, but i tried setting the system proxy and making sure the proxy can access workers.dev, but it still doesnt work
I also tried it without setting the system proxy env and it still crash...

--- 2025-07-04T13:45:13.989Z log
Proxy environment variables detected. We'll use your proxy for fetch requests.
---